Structure and morphology of dense polymer membranes with dispersed magnetic powder (magnetic membranes) for air separation were investigated. Qualitative and quantitative description of membrane structures based on fractal analysis, is presented. Box counting method for calculating the generalized fractal dimension was used. Structures with the same value of fractal parameters as for real membranes were simulated, and random walk dimensions were evaluated. Study of transport processes in air separation using polymeric membranes with magnetic powder both experimentally and through the random walk, was performed. The experimental results were compared with theoretical predictions. Finally, the diffusion equation with a spatial dependent diffusion coefficient of self-similar type to describe diffusion processes in the aforementioned membranes, was proposed. (c) 2012 Elsevier B.V. All rights reserved.